For machines, such as packaging machines, having movable tools, conveyor apparatus and the like, safety considerations have led to regulations requiring that the movable parts of machines be restricted from inadvertent or accidental access by operating personnel so as to protect the latter from injury. Such machines therefore have housings, linings and coverings with fixed wall elements, lids and doors. As a rule these elements, or their hinges, are screwed firmly to the machine frame. The assembly of such a housing represents a considerable expenditure of labor, which is particularly high because the individual parts of the housino must be adapted to one another.